1. Field of the Invention
The present invention relates generally to conveyor systems, and particularly to a system in which at least one pivoting conveyor section is arranged at a feed or delivery end of a feed conveyor for purposes of evenly distributing articles carried by the feed conveyor onto an accumulation slide.
2. Description of the Known Art
Many so-called overnight package delivery services now provide for guaranteed overnight delivery of documents contained in various kinds and sizes of envelopes usually provided by the service company. As the popularity and widespread usage of such document delivery services increases, so does the volume of envelopes destined to addresses located in a given area each day.
Packages and envelopes destined for different locations are usually picked up from various deposit locations and all transported together to a receiving station for sorting. The receiving station employs conveyor systems of the kind disclosed in my copending applications Ser. No. 917,783, filed Oct. 10, 1986, and Ser. No. 929,178, filed Nov. 10, 1986, both of which applications are now abandoned.
Small, flat packages such as envelopes containing documents or letters and destined to a particular geographical region, are initially sorted according to region and then placed on a feed conveyor which delivers the packages to another sorting area. There, the packages are caused by means such as paddles to be swept from the feed conveyor onto an accumulation slide extending adjacent and beneath the feed conveyor. The thus diverted packages land on the accumulation slide and descend to a level at which one or more persons sort the landed packages further according to their particular destinations which may be in the form of, e.g., a three-letter airport code or a five-digit address "zip" code.
A problem arises, however, when a relatively great number of packages destined for a particular region are diverted over a short period of time to land on the same accumulation slide. In such case, rather than assuming a fairly even distribution along the lower edge of the slide at which the packages are retrieved for further sorting, the packages will bunch together and, possibly, pile up on one another to such an extent that some of them will fall from the lower edge of the slide. The sorting personnel then must take the time to retrieve such documents from the floor. Also, a situation is created in which some of the documents may become lost.
An attempt to overcome the mentioend "bunching" of documents together on an accumulation slide adjacent a feed conveyor is known, wherein several paddles are arranged successively adjacent a feed conveyor in the region of the accumulation slide, and the paddles are operated sequentially to divert packages off the feed conveyor and onto the slide. When using successive paddles, however, problems arise in that letters or other relatively flat packages become lodged between the lower edge of a paddle and the surface of the feed conveyor, rather than being swept completely off the conveyor by the action of the paddle. Letters or flat packages jammed beneath an actuated paddle understandably may remain in such a condition without being noticed over a considerable length of time or, worse, can be damaged or mutilated after several actuations of the same paddle. Another problem with the known paddle arrangement arises if the clearance between the bottom edge of the paddle and the feed conveyor surface is too great, thus allowing relatively thin packages such as the now-popular "overnight" letters to run under the paddle and pass the accumulation slide for which they are intended rather than being diverted onto the slide by any of the associated paddles.
Tilt-tray systems are also known in which a series of trays linked to one another form a moving conveyor. Each tray is capable of rocking motion about an axis parallel to the direction of movement of the conveyor. When a tray carrying a package marked for a particular destination passes a corresponding receiving station, the tray is rocked to allow the package to fall from a side edge of the tray. Such a tilt-tray system does not, however, lend itself to facilitating an even distribution of packages across the breadth of an accumulation slide.